But while stepping on a bathroom scale every day is easy, it may not provide the best snapshot of the health risks that come from carrying excess fat, in particular weight around the abdomen.
Instead, a group of experts recommends measuring waist circumference, alongside body mass index (BMI) — a combination of height and weight — as a way to identify people with a higher risk of cardiovascular disease.
“Recent data highlight abdominal obesity, as determined by waist circumference, as a cardiovascular disease risk marker that is independent of body mass index,” they wrote in a new scientific statement from the American Heart Association
The authors also called for doctors to routinely measure patients’ waist circumference, which may be especially helpful for patients trying to lose weight.
”Patients should have their BMI and [waist circumference] measured not only for the initial assessment of the degree of overweight and obesity,” wrote the authors, “but also as a guide to the efficacy of weight loss treatment.”
Limitations of using BMI
Some clinical guidelines already call for physicians to measure waist circumference alongside BMI to identify patients most at risk from being overweight or having obesity.
But Robert Ross, PhD, an obesity researcher at Queen’s University in Kingston, Ontario, Canada, says more needs to be done to ensure that waist circumference is measured routinely like other vital signs.
“We measure blood pressure on all patients,” he said. “Waist circumference is no harder to measure than blood pressure. Why can’t we take another 2 minutes and measure their waist?”
The need for measuring waist circumference in the clinic stems in part from the limitations of BMI.
For example, weightlifters with very low body fat are sometimes misclassified as overweight or obese when using BMI because they have a high amount of muscle mass for their height.
For other groups, BMI provides a relatively clear picture of a person’s overall body fat, but it doesn’t show where the fat is located — which can affect a person’s health risks.
People who carry a lot of weight around their abdomen — an apple-shaped body — have a higher risk of heart disease, type 2 diabetes, and premature death.
These health risks are lower for pear-shaped individuals, those who carry more weight around their hips and thighs.
“Premenopausal women tend to accumulate excess adiposity, or weight, in the lower body,” said Ross, “which, with respect to health risks, tends to be more benign.”
Using BMI along with waist circumference helps doctors differentiate between these two body shapes.
In addition, using BMI alone may not capture the health risks for older adults.
As people age, they tend to lose muscle mass, but they may also gain weight around the abdomen. So, even if their overall weight — and BMI — stays the same, they may shift toward a body shape associated with higher health risks.
Measuring waist circumference would capture the shift in fat distribution.